This type of cushion usually comprises a base sheet from which there project a plurality of adjacent inflatable cells that are individually adjustable in height.
When in good condition and appropriately inflated, such a cushion gives satisfaction. Nevertheless, for a patient who does not feel pain, it is not possible to determine whether the cushion is appropriately inflated. In particular, if there is a loss of pressure because a valve has been torn off, because of a puncture, etc., then the effectiveness of the cushion diminishes without the patient being aware of it.
Furthermore, it is difficult to adjust the inflation pressure of the cushion since the pressure depends on each patient and on the patient'position when installed on the cushion. The greater the weight exerted by the patient on the cushion, the greater the extent to which the cushion should be inflated.